WHO confirms fatal Egyptian H5N1 caseThe World Health Organization (WHO) today confirmed the H5N1 avian influenza illness and death of a 20-year-old Egyptian woman whose infection was recently reported by the country's health ministry. The woman, from Qalyubia governorate, was hospitalized on Jul 21, where she received oseltamivir (Tamiflu) and was placed on a ventilator. She died Jul 27. The cases raises Egypt's number to 110, of which 35 have been fatal. In a statement today, the WHO said an investigation into the source of the woman's illness found that she had been exposed to sick and dead poultry. The global H5N1 case count now stands at 502 cases and 298 deaths, according to the WHO.Jul 29 WHO statement

Study projects social network effects on vaccine uptakeVaccine campaigns are very sensitive to small changes in perceived costs of vaccination, such as money, time, inconvenience, and possible side effects, according to Harvard University researchers who incorporated epidemiologic data into a game theory model of how social networking affects vaccination. They reported their findings yesterday in Proceedings of the Royal Society B. Their analysis found that small changes in vaccine costs prompt more "free riding," meaning people assume they are protected by herd immunity, as well as larger epidemics. Imitation behavior on social networks in a "vaccine scare" setting could drive vaccination rates down 14% and quadruple the size of flulike epidemics, they reported. In a Harvard University press release that accompanied the study, Daniel I. Rosenbloom, a graduate student in Harvard's Program for Evolutionary Dynamics, said altruistic behavior in an epidemic setting in social hubs can help increase vaccination rates, but he said self-interested motives—the desire to avoid getting sick—is enough to boost vaccine uptake.Jul 29 Harvard University press releaseJul 28 Proc R Soc Babstract

Legionnaires' cases reported at Michigan National Guard baseHealth officials at Selfridge Air National Guard Base, about 30 miles northeast of Detroit, are investigating a possible Legionnaires' disease outbreak that has sickened 31 people, with two confirmed cases of the disease, the Detroit Free Press reported today. During the outbreak, which occurred Jul 12 through Jul 24, six people were hospitalized and later released. Two buildings on the base were closed for sanitizing, and results from air and water testing is expected in the next 10 days. Legionnaires' disease, caused by Legionella bacteria, is a type of pneumonia that infects about 8,000 to 18,000 people each year, according to background information from the Centers for Disease Control and Prevention (CDC). Infections are fatal in 5% to 30% of patients. The bacteria can grow in warm water sources, such as air conditioning systems or hot tubs. People typically contract the disease by breathing in vapor or mist from contaminated water sources.CDC background information